Low power motors for power tools, domestic equipment, refrigerators, vacuum cleaners etc are typically supplied at 220V a.c. 50/60Hz. Common types are: Split-phase induction motor... Read more
There are three types of overcurrent relay (OCR) used for motor protection: Electronic Thermal Electromagnetic Electronic OCIT (overcurrent inverse time) relays have largely supers... Read more
Protecting an electric motor basically involves preventing the motor from getting too hot. Remember, every 10*C above the maximum recommended temperature of the insulation can redu... Read more
When motor direct-on-line started with the stator winding star connected, it will only take one-third of the starting current that it would take if the windings were delta connecte... Read more
When the 3-phase a.c. supply voltages are connected to the three stator phase windings, the resulting phase currents produce a multi-pole magnetic flux. This flux is physically rot... Read more
Ship’s Motor Enclosures Enclosure protection for electrical equipment is defined in terms of its opposition to the ingress of solid particles and liquids. The enclosure protection... Read more
The induction motor has two main components, the stator and the rotor. The stator carries three separate insulated phase windings which are spaced 120 degree (electrical) apart and... Read more
The central section of the main switchboard is used for the control of the main generators. The switchgear cubicles on either side of the generator panels are used for essential se... Read more
The power rating of an emergency generator is determined by the size and role of the ship. On some small vessels a few kW will suffice for emergency lighting only. Larger and more... Read more
Sudden load current surges (e.g. due to motor starting) on a generator cause a corresponding change in its output voltage. This is due to an internal voltage drop in the generator... Read more
